The immense diversity of organisms is one of the most striking features of ecosystems, but currently the majority of species is still undescribed and many species are threatened from extinction due to human impact. We aim to understand the ecological and evolutionary factors shaping the richness and structure of animal communities in natural and anthropogenic habitats. In our research we investigate the consequences of habitat fragmentation, climate change and invasive species on genetic, interaction and species diversity. We are particularly interested in the relationship between biodiversity and ecosystem functioning, the underlying ecological mechanisms and the socioeconomic consequences of biodiversity loss.
Biotic interactions and food webs
The complex mutualistic and antagonistic interactions between animals, plants, fungi and microorganisms play a major role for the structure and functioning of ecosystems. We are interested in the causal mechanisms and the direct and indirect impacts of these diverse interations on the reproduction and population dynamics of plants and animals, the stability of food webs and communities, and on related ecosystem processes. In particular, we investigate plant-pollinator, plant-herbivore, plant-ant and host-antagonist interactions. We study these interaction not only in easy to manipulate experimental systems but also at larger scales in real systems to better understand the effects of environmental change on biotic interactions and related ecosystem services.
Harmonia axyridis and Aphis nerii (D. Mahsberg)
Bombus lapidarius on Centaurea cyanus in an organic wheat field
Effects of global change
Global change covers the far-reaching anthropogenic changes of earth´ ecosystems caused by the destruction ad fragmentation of natural habitats, land use intensification, emission of green house gases, biotic exchange and overexploitation of natural resources. We study single and combined effects of habitat fragmentation, climate and land use change on species richness and biotic interactions such as pollination, herbivory and predation. Research approaches include the study of altitudinal gradients and fragmentation gradients in tropical and temperate habitats as well as the simulation of extreme climatic events.
Wild bee on Potentilla erecta: animal-plant-interaction
Obvious effects of an advanced snow-melt: advanced phenology of plants
Simulation of advanced and delayed snow melt
Early Bumblebee (Bombus pratorum) on moss campion (Silene acaulis)
Agroecology, forest ecology, biosafety research
A growing human population demands the majority off the terrestrial surface for agriculture, forestry and settlement. As a consequence highly diverse tropical rainforests and species-rich traditional agroforestry systems are lost at increasing rates. In our research we quantify the consequent biodiversity loss and search for sustainable agroforestry systems that might reconcile the production of food with the protection of biodiversity and ecosystem services. With a related motivation we study in European agroecosystems the role of local management, landscape structure and crop rotations on functional diversity and ecosystem services such as crop pollination and biological pest control. Further, we evaluate the effectiveness of agri-environmental schemes, the effects of biofuel crops and perform biosafety research on non-target effects of GMO´s on honeybees and other pollinators.
Most remaining conservation areas of natural habitats are small and isolated by a different landscape matrix from each other. We are interested in the factors that ensure long-term survival of endangered animal species, including local and regional habitat and landscape management, dispersal, ecological interactions, population dynamics, genetic diversity and adaptive capacity to changing climatic conditions.
Evolutionary Ecology and Population Genetic
Our research centers on the evolution of life history strategies – with a special focus on dispersal – and the implications of these strategies for biological diversity and species survival in spatially and temporally heterogeneous landscapes. It encompasses all aspects of dispersal evolution and its implications for species distributions and species survival under global climatic change, but also topics like the analysis of mutualistic and parasitic interactions, the evolution of species diversity, the evolutionary value of physiological clocks and adequate timing of life history events, and even studies on the evolution of sociality in insect colonies. Our work aims at a deeper understanding of evolutionary mechanisms and a further development of ecological theory, thus our group consists mainly of theoretical ecologists and we mainly use analytical approaches and computer simulations in our work.
However, in all our projects we strive for a close cooperation between theoreticians and modellers on the one and field ecologists and experimentally oriented ecologists on the other. Together with ecologists from other institutions we thus perform empirical investigations e.g. on the evolution of dispersal in spider mites (together with Dries Bonte, Ghent University), life-history trait evolution in antagonistic systems (together with Jeremy Thomas, Oxford and Karsten Schoenrogge, CEH Wallingford), the adaptive potential of amphibian populations (together with Marc. O. Rödel, Leibniz Institute for Research on Evolution and Biodiversity, Berlin) or the stability of plant-pollinator networks (together with Nico Blüthgen, Darmstadt).